Power converters, which receive an unregulated input voltage and convert the voltage to a specified level, are commonly used in electronic components. Designers of power converters such as point-of-load (POL) direct current to direct current converters DC—DC converters, and voltage regulator modules (VRMs) must satisfy increasingly stringent requirements established by manufacturers of electronic components such as processors. High power/current density, low output voltage deviation in both steady-state and transient conditions, high efficiency and physically small converters are just a few examples of the specifications that must be met by power converter manufacturers. The transient response (e.g., the time it takes for the output power levels to stabilize) and efficiency of the power converter are affected by these requirements.
Several actions may be taken to improve the transient response and the efficiency of a power converter. For example, the switching frequency may be increased. Decreasing the inductance of the output inductor also improves the transient response and efficiency of a power converter.
There are a few conventional approaches to address these problems. For both isolated and non-isolated topologies, paralleled synchronous rectifiers are typically used for high-current low-voltage converters. However, using synchronous rectifiers limits the ability to increase the switching frequency.
Another approach involves an interleaving technique applied to non-isolated step-down DC—DC power converters (also known as buck converters) and the interleaved series connected isolated topologies. Interleaved non-isolated buck topology is typically used in 5 volt (V) to 12V input VRMs or POL DC—DC converters where N converters are paralleled at the input and the output terminals. There are several disadvantages to these approaches such as the power converter having a relatively high current per channel, a higher switching frequency per switch, a smaller step down ratio for lower output voltages, and a high ripple effect (i.e., the AC component from a DC power supply arising from components within the power supply). What is needed is a device that overcomes these disadvantages.